FIR Completion: Fix completion in function calls (foo.bar<caret>())

In such expressions, `KtCallExpression` wraps `KtSimpleNameExpression`,
so `getQualifiedExpressionForSelector()` returns `null`

Also, enable tests that are fixed by this

idea/idea-completion/testData/basic/common/AfterIntSeparatedWithComments.kt

@@ -1,3 +1,5 @@
+// FIR_COMPARISON
+
 infix fun Int.func(s: String): Int{}
 
 fun test() {

idea/idea-completion/testData/basic/common/primitiveCompletion/extensionRecompletion.kt

@@ -0,0 +1,13 @@
+// FIR_COMPARISON
+
+class LocalClass
+
+fun LocalClass.ext(action: () -> Unit) {}
+fun LocalClass.extAnother(action: () -> Unit) {}
+
+fun usage(l: LocalClass) {
+    l.ext<caret> {}
+}
+
+// EXIST: ext
+// EXIST: extAnother

idea/idea-completion/testData/basic/common/smartCast/SmartCastAfterIfMethod.kt

@@ -1,3 +1,5 @@
+// FIR_COMPARISON
+
 class Expr {}
 class Num : Expr() {
     fun testing() {}

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JSBasicCompletionTestGenerated.java

@@ -2297,6 +2297,11 @@ public class JSBasicCompletionTestGenerated extends AbstractJSBasicCompletionTes
                 runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/extensionPropertyAndFunctionImplicitReceiver.kt");
             }
 
+            @TestMetadata("extensionRecompletion.kt")
+            public void testExtensionRecompletion() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/extensionRecompletion.kt");
+            }
+
             @TestMetadata("genericExtensionPropertyAndFunctionExplicitReceiver.kt")
             public void testGenericExtensionPropertyAndFunctionExplicitReceiver() throws Exception {
                 runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/genericExtensionPropertyAndFunctionExplicitReceiver.kt");

idea/idea-completion/tests/org/jetbrains/kotlin/idea/completion/test/JvmBasicCompletionTestGenerated.java

@@ -2297,6 +2297,11 @@ public class JvmBasicCompletionTestGenerated extends AbstractJvmBasicCompletionT
                 runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/extensionPropertyAndFunctionImplicitReceiver.kt");
             }
 
+            @TestMetadata("extensionRecompletion.kt")
+            public void testExtensionRecompletion() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/extensionRecompletion.kt");
+            }
+
             @TestMetadata("genericExtensionPropertyAndFunctionExplicitReceiver.kt")
             public void testGenericExtensionPropertyAndFunctionExplicitReceiver() throws Exception {
                 runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/genericExtensionPropertyAndFunctionExplicitReceiver.kt");

idea/idea-fir/src/org/jetbrains/kotlin/idea/completion/KotlinFirCompletionContributor.kt

@@ -21,7 +21,7 @@ import org.jetbrains.kotlin.idea.frontend.api.symbols.markers.isExtension
 import org.jetbrains.kotlin.idea.references.mainReference
 import org.jetbrains.kotlin.lexer.KtTokens
 import org.jetbrains.kotlin.psi.*
-import org.jetbrains.kotlin.psi.psiUtil.getQualifiedExpressionForSelector
+import org.jetbrains.kotlin.psi.psiUtil.getReceiverExpression
 
 class KotlinFirCompletionContributor : CompletionContributor() {
     init {
@@ -74,7 +74,7 @@ private object KotlinAvailableScopesCompletionProvider {
         val reference = (parameters.position.parent as? KtSimpleNameExpression)?.mainReference ?: return
         val nameExpression = reference.expression.takeIf { it !is KtLabelReferenceExpression } ?: return
 
-        val explicitReceiver = nameExpression.getQualifiedExpressionForSelector()?.receiverExpression
+        val explicitReceiver = nameExpression.getReceiverExpression()
 
         with(getAnalysisSessionFor(originalFile).createContextDependentCopy()) {
             val (implicitScopes, _) = originalFile.getScopeContextForPosition(nameExpression)
@@ -128,9 +128,7 @@ private object KotlinAvailableScopesCompletionProvider {
 
         val extensionsWhichCanBeCalled = implicitScopes
             .getCallableSymbols()
-            .filter {
-                it.isExtension && it.hasSuitableExtensionReceiver()
-            }
+            .filter { it.isExtension && it.hasSuitableExtensionReceiver() }
 
         availableNonExtensions.forEach { result.addSymbolToCompletion(it) }
         extensionsWhichCanBeCalled.forEach { result.addSymbolToCompletion(it) }

idea/idea-fir/tests/org/jetbrains/kotlin/idea/completion/HighLevelJvmBasicCompletionTestGenerated.java

@@ -2297,6 +2297,11 @@ public class HighLevelJvmBasicCompletionTestGenerated extends AbstractHighLevelJ
                 runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/extensionPropertyAndFunctionImplicitReceiver.kt");
             }
 
+            @TestMetadata("extensionRecompletion.kt")
+            public void testExtensionRecompletion() throws Exception {
+                runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/extensionRecompletion.kt");
+            }
+
             @TestMetadata("genericExtensionPropertyAndFunctionExplicitReceiver.kt")
             public void testGenericExtensionPropertyAndFunctionExplicitReceiver() throws Exception {
                 runTest("idea/idea-completion/testData/basic/common/primitiveCompletion/genericExtensionPropertyAndFunctionExplicitReceiver.kt");